1. Field of the Invention
The present invention relates to a semiconductor laser apparatus for information processing for writing DVDs, or a semiconductor laser apparatus for an pumping light source or for optical communication, such as a solid state laser (e.g., an Nd doped YAG (Nd:YAG) laser, a Yb doped YAG (Yb:YAG) laser, or the like), a Yb-doped fiber laser, an Er doped fiber amplifier, etc.
2. Description of the Related Art
Conventionally, in order to provide a semiconductor laser apparatus capable of high output operation, there has been proposed a structure in which an active layer of GaAsP is sandwiched between a pair of optical guide layers of AlxGa1-xAs having the same thickness and composition (see, for example, a later-mentioned first non-patent document).
In addition, in such a kind of semiconductor laser apparatus, the slope or gradient of a carrier distribution in a p-side guide layer is μn/μp of that of a carrier distribution in an n-side guide layer (see, for example, a later-mentioned second non-patent document).
[First Non-patent Document]
J. Sebastian, et. al., “High-Power 810-nm GaAsP—AlGaAs Diode Lasers With Narrow Beam Divergence”, IEEE J. Select. Topics Quantum Electron., vol. 7, No. 2, pp. 334-339, 2001
[Second Non-patent Document]
M. Alamand, M. Lundstrom, “Simple Analysis of Carrier Transport and Buildup in Separate Confinement Heterostructure Quantum Well Lasers”, IEEE Photonics Technol. Let., vol. 6, No. 12, pp. 1418-1420, 1994
In the conventional semiconductor laser apparatus, there is an increasing demand for improving an electric conversion efficiency (optical output/input electric power) so as to reduce power consumption, but there has been a problem that a technique for reducing optical absorption by increasing the thickness of the guide layers for improved slope efficiency,